1. Field of the Invention
Embodiments of the invention generally relate to an elongate implantable electrical line including an end component at one longitudinal end of the electrical line, wherein the end component includes at least one electrically conductive electrode surface electrically connected to the electrical line.
2. Description of the Related Art
Generally, elongate implantable electrical lines typically include electrode lines such as stimulation electrode lines for implantable cardiac pacemakers or defibrillators. Such electrode lines, typically, include a proximal end with an electrical terminal for connection of the electrode line to a stimulation device, such as a cardiac pacemaker or defibrillator, and also a distal end with stimulation or sensing electrodes. Generally, an electrode head is often arranged at the distal end of an electrode line and forms a tip electrode. Typically, one or more ring electrodes may also be provided at a short distance from the tip electrode.
European Patent 0787507 to Ekwall, entitled “Medical Device Used to Stimulate Tissue”, appears to disclose a stimulation electrode line, wherein a metal electrode is completely coated with an insulating layer. The device of Ekwall uses, for example, titanium as the metal of the electrode, and titanium oxide as the insulating layer on the electrode with a layer thickness of 1 μm. According to Ekwall, aluminum may be used as the metal of the electrode and aluminum oxide as the material of the insulating layer.
Ceramic layers have also been utilized with electrodes. Generally, ceramic layers have the disadvantage of having small holes or imperfections, also referred to as pinholes, which may cause a metal layer of an electrode line to no longer be galvanically isolated from the environment surrounding a composite component of the electrode line.
Typically, an outer ceramic layer is mechanically and chemically stable, even at low thickness, however ceramic layers are typically sensitive to electrical effects, such as spark erosion. Generally, small imperfections in the coating (such as the pinholes) lead to formation of plasma channels in the event of an electrical load. Generally, the plasma channels, in the event of an electrical discharge, generate temperature peaks that lead to damage of both an insulating layer and a support layer. Typically, any damage of this type may lead to malfunction of the electrode in the event of sensing or stimulation (such as pacing). Generally, a mere increase of the layer thickness of the ceramic layer does not increase the long-term stability thereof since pinholes typically cannot be closed or avoided by increasing the layer thickness.
In view of the above, there is a need for an electrode line with a composite component, a thin metal layer and a ceramic layer, such that, in the event of a pinhole, the thin metal layer not located in the region of the pinhole is electrically insulated from the environment surrounding the composite component.